Stationary induction apparatus



Sept. 22, 1953 o. KILTIE 2,653,280

STATIONARY INDUCTION APPARATUS Filed June 17, 1949 FIE: 1'.

FIE- E.

INVENTOR.

A TTORNYS Patented Sept. 22, 1953 STATIONARY INDUCTION APPARATUS Ordean Kiltie, Fort Wayne, Ind., assignor to Ballastran Corporation, Fort Wayne, Ind., a corporation of Indiana Application June 17, 1949, Serial No. 99,713

3 Claims. (01. 317-165) This invention relates to stationary induction apparatus and is particularly directed to the core structure of a transformer having a deliberately introduced leakage path to provide for operation of a magnetically sensitive external device.

The primary object of the invention is to provide a core structure for an apparatus of the above character which shows greatly increased eificiency over known units of a similar nature.

Another object of the invention is to provide a core structure which is simple and efficient in operation, easy to assemble and which cannot become misadjusted after assembly.

Another object of the invention is to provide a core structure for an induction apparatus composed of a series of laminations of varying size and shape to direct the flux through the transformer into a particular path for increased effectiveness in the operation of an external magnetically sensitive device.

Other objects and advantages of the invention will become apparent from the following specification, reference being had to the accompanying drawings in which:

Fig. 1 is a circuit diagram showing a typical circuit in which the present invention is usable; Fig. 2 is a diagrammatic side elevation, with parts broken away, of a unit embodying the present invention; Fig. 3 is a bottom elevational view of the unit; and Figs. 4 and 5 are sections on lines 4-4 and 5-5, respectively of Fig. 2.

Referring to the drawings, and particularly to the circuit diagram of Fig. 1, the present invention is particularly directed to the core structure of a transformer diagrammatically indicated at T. The transformer is shown as being of the auto-transformer type although separate primary and secondary windings may be provided if desired, rather than the tapped single winding indicated. The transformer is associated with a power source It) such as a battery having one side grounded and with a glow discharge lamp H in series with one winding of the transformer, the other winding being grounded. Power is applied to the center tap of the transformer in the usual manner through a switch I2 having a shunting capacitor l3 to reduce arcing at the switch points as the switch is opened and closed. In the device shown the ratio of turns in the transformer windings is such that discharge occurs in the lamp II from the power source whenever switch I2 is opened and the flux in the core collapses.

As indicated in Fig. 2 the transformer is of the core type, and the core preferably comprises generally, a series of U-shaped laminations having the open leg closed by straight laminations designated M. The transformer winding is disposed around one leg of the core and switch I2 is associated with another leg which will be presently described.

Switch i2 is preferably of the hermetically sealed type with the switch elements housed in a glass envelope, designated l5. One of the switch elements, designated It, remains substantially stationary while the cooperating element i? is drawn into and out of engagement with the stationary element as flux in the core rises and falls as hereinafter described. Element I1 is made of a magnetic material such as soft iron and is pivoted about the point where it is sealed in the glass envelope [5. The normal position of the element is as indicated in the drawing, in the closed position against contact It. Element H is drawn out of position against its biasing spring force by any magnetic attraction operating in a direction perpendicular to the plane of the stationary contact.

By reason of its close association with the transformer core it will be seen that sufiicient leakage flux from the core would draw movable contact I! out of position and break the circuit between contacts [6 and I1. By the present invention such leak-age flux is deliberately introduced in an improved manner and concentrated at the exact point where it is needed. The leakage flux can, of course, be caused by an air gap in those transformer laminations immediately adjacent the point of closest approach of contact I! to the core. Since an air gap causes dispersion of the flux in all directions, where a concentration of the flux in paths which will include the movable switch arm I! is desired, the present invention is directed to causing definite flux concentration. Thus the immediately adjacent outer core laminations are provided with a toothed form of air gap designated l8 having relatively wide side portions and more closely spaced center portions [9 facing each other. As indicated in Fig. 5 the teeth l9 are immediately adjacent the point of closest approach of the movable switch arm l'l. Since flux across the air gap 18 will be principally concentrated in the teeth 49 a very large portion of the flux flowing in the laminations, of which the teeth are a part, will pass across the gap formed by the teeth and a portion of this flux will link the movable switch arm. Since the flux field tends always to contract, the arm is drawn in a direction toward the core and the contacts I6 and I l are separated and the circuit with which they are associated opened.

nated 2 I, may be made of a highly permeable ma terial to increase the flux in the circuit while the discontinuous laminations including"? air. gap 20.

and operating air gap l8 may be madeoramaterial of higher reluctance.

The time required for flux build-up is-gcverned not only by the reluctance of the magnetic path, but may also be altered by the provisionor a shorting or shading turn in the form of a copper or similar electrically-conducting non-magnetic strap 22 indicated principally in Fig. ii The strap 22 may also be conveniently used: to hold the switch envelope I5 in its proper physi cal relation to the core parts. The strapitmay be adjusted lengthwise of the core and switch-errvelope' and. will, in some measure, affect the rapidity with which the flux rises and decaystin the: core and. thusthe periodicity of the flashaof; lamp l1l:..

In operation, once the circuit shown in".Fig;.1x

is established with switch v l'2 closed, current will.

flow through the transformer and flux: in the. core will build up. When the flux in thetrans formercore builds up, a certain proportion of it:

leaks through the gap 3- and is diverted outw-ardly to include the movable'switch arm. H in. the magnetic circuit; When sufficient flux has been built up and so diverted, the contractingforce of the magnetic field established thereby draws the movable contact l1 out of its position against the stationary contact l6 and opens the circuit. The rapid decay of flux causesth'e lamp wherethe' spring force of movable" arm I? can again return the arm to its circuit closingposi tion, the-circuit is reestablished and-flux buildup in the" core starts again in the next cycle. The lamp H thus flashes onand oifand-fiash'-- ing' will continue as longas thebattery' I0 is capable of furnishing sufflcient energy to-causethe discharge Since the only waste energy in the system is the iiux leakage out of the core. and since such leakage" is deliberately" introduced; it is; of course; highly desirable that the leakage be confined to' that portion of the corewhere'it" is needed for operation of magnetic switch arm IT.

While-the invention" has been disclosed in" con:- nection with a specific form and disposition. of? thepart, it will be appreciated that certain modifi'cations andchanges may be made th'ereinwithout departing from the" scopeiof the appended:

claims;

What I claimis:

l. A stationary induction apparatus" for; the operation of an external unit havingia flux respons'ive element movable in a fixed p'ath,,.s'aid1 apparatus comprising. in combination, a stacked. laminatedclosed core for establishing amagnetici circuit adjacent said external'unit,-. said. fl'ux responsive element being, positioned adjacent the.

broad face of an outermost core. lamination,,a.

flux' leakage path in lineand1under. said flux responsive element, said flux leakage path: com.-

prising a partial air gap in the outer lamination's of the core nearest said flux responsive element, said outer laminations being continuous along their longitudinal edge portions, means for increasing the flux concentration under said flux responsive element, comprising a larger air gap in the intermediate laminations directly under said outer laminations and; said flux responsive element; said intermediate laminations being completely discontinuous where they form said larger air gap.

LA; stationary induction apparatus for the operation of an external unit having a flux respons-ive element mbvable in a fixed path, said apparatus comprising in combination, a stacked laminated closed core for establishing a magnetic circuit) adialcent said external unit, said flux responsive element being positioned adjacent the broad face of an outermost core lamination, a flux leakage path in line and under said flux responsive element. said finx' leakagepath: comprisingv a. partial air' gap: in: the outer" laminae tions of the: core nearest. said flux" responsive element; said outer: laminationss being continui- 01154310118 theirlongitudinalteuge portions,.means: for increasing the flux concentration under: said; flux responsive element, comprising ailarger: air gap in the: intermediate laminations directly undersaid outer laminations and said: flux re sponsive' element} said intermediate laminations being completely discontinuous where they form said larger air -gap an'd means iormounting the external unit on said laminated core" comprising an electric conducting non-magneticstrap disposed partially around said core and said external unit.

3: A stationary induction apparatus for the operation of an external un-it having aflux responsive element movablein" afixed'pa-th'; said apparatus comprising in combination, a stacked laminated closed core for establishing a mag-- netic circuit adjacent said external unit, said flux responsive element being positioned adjacent the broad face of an outermost core lamina-- tion, a flux leakage path in line and under said flux' responsive element, said flux" leakage path comprising a partial air" gap in the outer. 1aminations' of the core nearestt said" iiux' responsive" element, said outer laminations being continuous" along their longitudinal edges. and? having. a large discontinuance in; those portions adjacent said longitudinal edges and a smallert discontinuance in the central'portion of said". lamina-.- tions; meansfor increasing theflux-iconcentratibn:

. under said flux responsive element comprising a' much larger air gap' in the intermediate lam! inations directly. under said outer laminations' and said flux responsive element; said intermedis ate laminations being. completely discontinuous where they" form said much larger air gap.

ORDEAN References Cited. in: the of 1 this. patenti- UNITED STATES PATENTS Number Name Date 1,940,496- James a Dec; 1.9 1-933 2,025,235. Gonsett Dec; 24,! 1.935 2,170,446 Edwards. Aug. 22,. 1 939- FORE'IGN' PATENTS Number Country Date.

604,525 Germany Oct. 22, 19341- 621300 Great Britain .Apr. 20,; 1949 

